The Study Of Adiponectin On The Bone Microenvironment Oxidative Stress And Bone Resorption In Type 2 Diabetic Rats

Objective: Observing the effect of adiponectin on the expression of tartrete-resistant acid phosphatase(TRAP)and the ratio of osteoprotegerin(OPG)and receptor activator of Nuclear Fator-?B ligand(RANKL)in the tests of type 2 diabetic rats,combined with the changes of advanced glycation end products(AGEs)and advanced oxidation protein products(AOPP),it is to explore the mechanisms of adiponectin which influence the osteoclast metabolism through oxidative stress in diabetes.Methods: 4 week old male SD rats were randomly divided into normal control group(n=18)and diabetic model group(n = 42).The rats in the control group were fed with normal diet.The rats in the model group were fed with high cholesterol and high glucose for 2 months,and then were injected a single intraperitoneal injection of streptozotocin of 30mg/kg to prepare type 2 diabetic model.The successfully-induced diabetic rats were divided into diabetic group(DM=18)and adiponectin intervention group(APN=18),then the rats in APN group were injected with APN 10 g/kg·d by intraperitoneal injection.The rats were sacrificed at 4,8 and 12 weeks after the intervention,removed the bilateral femur and tibia,extracted the bone marrow from one side of femur and tibia,and then obtained bone marrow cells and bone marrow supernatant by centrifugation.After bone density measurement and decalcification in EDTA,the other side of the femur and lumbar spine was embedded in paraffin and 4-7?m sections was cut.ELISA and RT-PCR were used to detect the expression of TRAP,RANKL,OPG,AOPPs and AGEs in bone tissue.HE staining was used to observe the bone microstructure(trabecular bone density and cortical thickness)and the amount of fat cells.Results:1.With the extension of feeding time,the level of blood glucose of DM group was significantly increased.After APN intervention,the level of blood glucose was improved.2.With the extension of feeding time,there was no significant change of AOPP and TRAP in normal group.However,the AOPP and TRAP level in the DM group and APN intervention group increased(P<0.05),but the increase of APN intervention group was smaller than that of DM group.At 4 weeks,the level of AOPP and TRAP in the DM group was higher than that in the control group(P<0.05);there was no significant difference between APN group and DM group.At 8 and 12 weeks,the AOPP and TRAP level were significantly higher in the DM group(P<0.05).After the intervention of APN,the level was lower than that of DM group(P<0.05),and the level decreased significantly in 12 weeks than in the 8 week.3.With the change of time,the expression of AGEs in bone tissue of normal rats was not significantly different;the expression of AGEs was increased in DM group and APN intervention group(P<0.05),but the increase amplitude of APN intervention group was smaller than that of DM group.At 4 weeks,the expression level of AGEs in the DM group was higher than that in the control group(P<0.05);compared with DM group,the expression of AGEs decreased after APN intervention(P<0.05).At 8 and 12 weeks,the expression of AGEs in DM group was significantly higher(P<0.05);compared with DM group,the expression of AGEs decreased after APN intervention(P<0.05),and the AGEs decreased significantly in 12 weeks than in the 8 week.4.With the extension of feeding time,the OPG leves in each group was gradually decreased,and the expression level of RANKL m RNA was gradually increased.At 4 weeks,there was no significant difference in the expression of OPG and RANKL in the three groups.At 8 weeks,compared with the normal group,the expression of OPG m RNA in DM group was significantly lower and the expression level of RANKL was significantly increased(P<0.05),after the intervention of adiponectin,the expression of OPG m RNA in APN group was significantly higher than that in DM group,and the expression of RANKL m RNA was significantly lower than that of DM group.At 12 weeks,the difference between the two groups was more obvious.The OPG/RANKL value and OPG m RNA expression levels were consistent(P<0.001).5.The BMD values of the three group were decreased compared with the 4 week and the 12 week,especially in DM group.At 4 weeks,the BMD difference was not statistically significant between any two groups,and trabecular structure did not change significantly.But at 12 weeks,the BMD in the DM group was lower than that in the control group,and it was significantly higher than that in the DM group after the APN intervention(P<0.05)and the trabecular structure improvement(P<0.001).Conclusion 1.Type 2 diabetic rats induced by glucose metabolism of bone marrow microenvironment increased glycosylated end product formation,oxidative stress levels increase,may have a direct effect on the bone marrow of rats with type 2 diabetes OPG/RANKL ratio in the micro environment.Combined with TRAP significantly increased,it is indicated that osteoclast differentiation can promote bone formation increased,the absorption process and accelerate bone lost.2.The adiponectin may reduce the formation of AGEs and the level of oxidative stress in diabetic rat bone marrow microenvironment in bone cell differentiation,reducing the broken bone marrow of rats with type 2 diabetes,which has significant positive effect on bone metabolism.